In 2010, the EPA announced it would start evaluating Appalachian coal mine permits based on conductivity. Conductivity is the measure of dissolved solids—typically sulfates—in a waterway, and science has shown that elevated levels impair streams.

Under Section 402 of the Clean Water Act, Kentucky is given the authority to issue permits for water pollution, while the EPA still has final authority over the process. The ruling earlier this week was that the agency couldn’t use this benchmark as a basis for rejecting permits. But the agency still has the authority to review and veto permits, and attorney Tom FitzGerald of the Kentucky Resources Council says the ruling doesn’t put the conductivity issue to rest.

“This will change somewhat the way that they approach that,” he said. “But if anyone thinks this gives a green light to the coal industry to damage streams with elevated levels of sulfates, they have another think coming.”

Last year, the agency issued specific objections to 36 Kentucky coal mine permits, partially on the basis of conductivity. FitzGerald says the recent ruling doesn’t mean those permits will automatically be approved—it will just force the EPA to change the way it addresses conductivity.

“Nothing in the rejection of that guidance prevents EPA from saying to a state, ‘We don’t believe you have addressed the potential for sulfate discharges here, and we believe that this permit will cause a violation of your approved water quality standard.’”

Kentucky Department of Environmental Protection Commissioner Bruce Scott agrees that there are still a number of unanswered questions when it comes to federal government involvement in the permitting process.

“The only thing it changes is, as far as the court is concerned, is how the EPA is to oversee the activities of the delegated states under the 402 program,” he said. “And that still has a number of unanswered questions that are associated with it. We don’t know for example how the EPA will view this ruling, in the context of how its oversight should or shouldn’t be.”

The ruling also doesn’t necessarily provide the regulatory certainty that coal industry officials and regulators have recently been clamoring for, because the legal process may drag on for longer if the EPA appeals the ruling. But regardless, the agency can still take other steps to determine that sulfate discharges violate a state’s water quality standard and require conductivity be addressed.